Correlation between SPAD and chlorophylls a, b and total in leaves from Vaccinium corymbosum L. cv. Biloxi, Legacy and Victoria in the high tropics Autor Pinzón-Sandoval, Elberth Hernando, Almanza-Merchán, Pedro José, Cely-Reyes, Germán Eduardo, Serrano-Cely, Pablo Antonio, Ayala-Martínez, Guillermo Alexander